ISLESBORO, Maine — A land trust that opposes the controversial $12 million Searsport Harbor dredging project commissioned a study that reports it has found a cheaper, less environmentally damaging alternative.

“It’s a game changer, no question about it,” Steve Miller of the Islesboro Island Trust said of the so-called non-structural alternative to the proposed project, developed by Washington-based firm Dawson & Associates.

The alternative would limit the amount of dredging required in Searsport Harbor by bringing the entry to Mack Point down to 35 feet and deepening the berths near the piers to 45 feet, according to the 18-page report released Thursday morning at a press conference held at the Capital Hall of Flags in Augusta.

Dawson & Associates engineers came up with the new conclusion after reviewing a feasibility study and environmental assessment done by the Army Corps of Engineers, which proposed a much larger dredging project in the harbor.

The alternative would require large, deep-draft vessels to get into the port at high tide. Once they’re in, the ships could unload cargo over “however many tide cycles they need,” because the berths would be deep enough for them to remain safely at the dock, Miller said.

But a supporter of the original dredging project has pointed out that the new study contradicts a prior study, also commissioned by the Islesboro Islands Trust, conducted a couple of years ago. At that time, the land trust was fighting a liquid propane gas terminal and storage tank proposed for Mack Point, and national security expert Richard A. Clarke’s consulting firm found the shallow navigational channel at Mack Point posed a threat to maritime safety.

“There is insufficient water depth in both the harbor and at the pier for the intended deep-draft [liquified petroleum gas] import vessels; dredging must be completed to ensure under-keel clearance requirements,” the Islesboro Islands Trust wrote in a press release issued Jan. 14, 2013.

David Gelinas of the Penobscot Bay & River Pilots Association said the new study sounded somewhat perplexing.

“Which expert are we supposed to believe?” he asked Wednesday. “The next thing you know, the Islesboro Islands Trust will be commissioning a study to study their studies to find out which one was right.”

As proposed by the Army Corps of Engineers, the Searsport Harbor project would dredge nearly 900,000 cubic yards of silt and sediment to enlarge the entrance channel and turning basin that leads to the Mack Point industrial port. Another 37,000 cubic yards of material would be dredged to maintain the federal navigation channel to a depth of 40 feet. The channel hasn’t been touched since it was originally dug to a depth of 35 feet in 1964 and now contains portions that are only 33 feet deep.

Opponents of the project, such as the Islesboro Island Trust, many environmental advocates, some state representatives and area lobstermen, have a variety of concerns, including whether the dredged material might be contaminated. Enough mercury has been found northeast of Mack Point to close upper Penobscot Bay to lobster and crab fishing; fishermen and others are worried about where the dredged material will be dumped.

“It’s an incredible alternative that needs to be considered,” Miller said of the new commissioned study. “It may be the answer. And if nothing else, it needs to be considered.”

But bay pilots such as Gelinas say the proposed alternative does not sound like a game changer that will solve the area’s navigational challenges.

“The bottom line is that the channel was designed 50 years ago, and the reality is that ships have gotten larger,” he said. “We’ve played the tide. This is not a new practice. This is something mariners do around the world, but it’s a balancing act and doesn’t address having a more efficient port, or addressing the greater safety standards of today.”